One problem with plastic containers designed to hold liquids is that the containers are permeable to certain liquids, to gas vapors of the liquid, and to other gases.
One specific example of the fluid transmission problem mentioned above involves plastic containers made from polyethylene terephthlate used to hold carbonated beverages. Transmission of CO.sub.2 through the polyethylene terephthalate containers results in a loss of the carbonization and thus limits the shelf life of the container. Another specific problem involves liquor containers made from polyethylene terephthalate which is also permeable to H.sub.2 O such that transmission of H.sub.2 O of the liquor outwardly through the container reduces the volume of the container contents and simultaneously increases the proof level. Likewise, other plastics which have good resistance to the transmission of certain fluids are permeable to other fluids. For example, the transmission of O.sub.2 into a plastic container affects flavor, color, and bacteria growth of food contents.
In order to overcome the fluid transmission problem mentioned above, one approach has been to coat the plastic container with a barrier material such as polyvinylidene cloride (PVDC). Such a coating has previously been applied by a dip method to the exterior of the container; however, it has been found that this results in the fluid contents causing blistering of the coating and a consequent unsightly appearance as well as allowing the loss of some fluid contents. This outside coating also results in additional time and labor as well as problems involved with providing an even distribution of the coating.
In addition to the outside coating mentioned above, inside coating of the container with the barrier material has also been considered. However, such inside coating is difficult to perform and requires increased drying time. Furthermore, the inside coating can result in flaking of the coating and consequent contamination of the container contents as well as requiring the additional time and labor involved with the exterior coating.
Plastic sleeves have also been used over platic containers such as shown in U.S. Pat. Nos. 4,183,441; 4,219,124; 4,315,573; and 4,342,399 to provide labelling, seam strengthening, upright support of an unstable container, strengthening, and the resistance of fluid transmission by the use of a metal foil of the sleeve. However, such sleeves due to the cost involved and other reasons have never found widespread acceptance.
Plastic blow molding on a commercial level has recently incorporated the use of in-mold labelling to provide labelling of containers such as shown by U.S. Pat. Nos. 3,108,850; 3,207,822; 3,292,209; 3,324,508; 3,608,020; 3,801,689; 3,986,807; 4,355,967; 4,359,314; 4,397,625; 4,479,770; 4,479,771; 4,479,644; 4,498,854; and 4,501,548. This in-mold labelling is performed by applying a label to the interior of the mold prior to the plastic blow molding process. The resultant blow molded article is then blown around the label and advantageously eliminates the necessity for a post labelling operation as has been required in the past. However, such in-mold labelling has not previously been capable of reducing the transmission of fluids through the container side wall.